Various devices have been employed for testing mechanical transmission components. Many testing devices have attempted to simulate actual running load conditions. With respect to torque transmitting components, a typical testing apparatus has been disclosed in U.S. Pat. No. 2,981,103 issued Apr. 25, 1961 to W. G. Livezey. The apparatus disclosed in such patent provided a closed type drive system in which the input and output for the apparatus were interconnected. Systems of such type generally included two transmissions interconnected by two connecting lines with the specimen component being positioned within one of the connecting lines and with the apparatus further including a torque applier which induced a torque or twist to the system.
Testing apparatus of this general nature for inducing torque strains on a test specimen were also disclosed in German patent document E-OS No. 15 73 682 which illustrated a torque testing apparatus in which the shafts of the two transmissions were mutually offset to provide testing torque loads for components such as universal joint shafts. Such apparatus thus provided a simulation of operating conditions wherein a universal joint shaft rotated at certain offset angles. In addition, torque testing apparatus of this general type was also disclosed in the Journal, ATZ 1963, no. 8, August 1961, at pages 239 through 242.
Typical torque transmitting components suitable for testing with the apparatus heretofore disclosed included mechanical transmission or drive components such as shafts, clutches, joints, gears, and the like. During a testing procedure, test specimens were acted upon in the testing apparatus by changing loads during a test run according to a predetermined testing program. Ideally, the components were tested under stress conditions which truly simulated actual running load conditions in usage.
The specimen components were required to have an induced torsional stress which possibly was very high, while the driving power required to rotate the specimen component was relatively small.
Ideally, a testing apparatus should have the capability of applying torque loads to the specimen when the specimen is not rotating and in addition to apply torque loads to a rotating component with random changes in intensity and direction.
Generally, the torque test apparatus heretofore known have been subject to significant disadvantages. In order to generate the requisite torque loads, relatively complicated torque appliers were employed. Such devices necessarily included housings, hollow shafts and bearings and were relatively large in mass to provide requisite torsional rigidity. For example, the torque applier of U.S. Pat. No. 2,981,103 included multiple planetary gear sets, clutch assemblies and brake assemblies. In devices of this nature it was inherently difficult to provide rapid changes in direction of applied torque, rapid speed changes, and other true load conditions in simulation of actual usage. In addition, the induced torque load from the torque applier to the test specimen in U.S. Pat. No. 2,981,103 was transmitted through a pair of pinions, a pair of shafts and a torque meter. By providing such indirect and lengthy transmission route, torque loads in true simulation of actual conditions were difficult to achieve and the possibility of twist deflection occurring in the route between the torque applier and the test specimen was present.